The contract is a continuing effort to produce a nonhuman primate model of excessive aggression and violence. It has two parts: 1.) To continue to longitudinally follow males which were selected as a part of the initial contract award, and 2.) To behaviorally and physiologically assess a group of female subjects with low CSF 5-HIAA concentrations. To assess these females, we propose to longitudinally investigate the development of excessive aggression and to identify prior to adolescence, markers and behaviors which can be used to predict female subjects at risk for problems of aggression and social adjustment. The data collected from the aggressive males provide a unique opportunity to longitudinally assess adult outcomes using data collected from these subjects that were obtained early in life. Because highly aggressive rhesus monkeys rarely occur and are usually not maintained in laboratory environments, the major objective of this study is to identify aggressive female subjects for longitudinal study, and to study their developmental adjustment and outcome. To investigate the underlying biological correlates of excessive aggression and competent social behavior, CSF, blood, skin biopsy, and activity samples will be collected from these female subjects. In both the females and males, data investigating how the gene is passed on to the next generation will be collected. These samples will be correlated with the subjects\rquote aggressive behavior, short- and long-term adjustment into normative monkey society, reproductive success, and in this continuing contract, maternal skills.